Nervous System Chapter 15 Medical Terminology Nervous System Chapter 15

Nervous System Coordinates many activities of the body senses changes in internal and external environment interprets these changes coordinates appropriate response in order to maintain homeostasis When the brain ceases functioning, the body dies

Structures nerve is one or more bundles of impulse carrying fibers that connect the brain & spinal cord with body

Nervous Tissue Neurons - transmit impulses Neuroglia - support neurons sensory (afferent, ascending) motor (efferent, descending) Neuroglia - support neurons

Neuron dendrites-rootlike structures that receive impulses and conduct them to the cell body cell body - contains nucleus axon-extends away from the cell body and conducts impulses away from the nerve cell

Neuron Anatomy Myelin sheath - insulation accelerates impulse transmission appears as white covering myelin on axons in brain and spinal cord gives white appearance unmyelinated fibers, dendrites, and nerve cell bodies comprise gray matter of brain and spinal cord

Neuron Anatomy (peripheral nerves) Schwann cell type of neuroglial cell wrapped around axon forms the myelin sheath Neurolemma (neurolemmal sheath) permits a damaged axon to regenerate neurolemma NOT found in Central nerves

Neurotransmitters Synapse- space between two neurons or between a neuron and a receptor organ. Impulses are passed from one neuron to another at a junction called the synapse. Electrical current within neuron causes release of chemical substance called a neurotransmitter.

Neurotransmitter diffuses across the synapse to receptor sites on the dendrite of the next neuron. Generates the next electrical stimulus. Terminal ends of the axon release a transmitter substance that affects the dendrites of the next neuron. One way transmission of the impulse is assured because only the axons release these chemicals.

Neuroglia gli/o or nerve glue neuroglia or glial cells astrocytes - blood brain barrier oligodendrocytes - facilitate myelin development microglia - phagocytic properties ependyma - assist in CSF circulation

Divisions Central Nervous System Peripheral Nervous System brain and spinal cord Peripheral Nervous System cranial nerves and spinal nerves fibers are sensory or motor Autonomic Nervous System ganglia on either side of the spinal cord sympathetic nervous system parasympathetic nervous system

Brain Cerebrum Cerebellum Diencephalon Brainstem

Cerebrum Cerebrum Cerebellum Medulla Oblongata Two hemispheres divided by a fissure Lobes frontal, parietal, temporal, occipital Cortex, gray color

Lobes Frontal Parietal Occipital Temporal motor functions receives & interprets information Occipital eyesight Temporal hearing & smell

Cerebellum receives incoming messages regarding movement within joints, muscle tone, and position of the body. relay these messages to other parts of brain to control skeletal activity movement, coordination, balance

Thalamus below the cerebrum monitors sensory stimuli by suppressing some and magnifying others

Hypothalamus-a regulator Autonomic Nervous System emotional responses/behavior body temperature food intake= hunger water balance and thirst sleep-wake cycles endocrine system activity

Brainstem stalk-like portion of the brain midbrain - conduction pathways pons - nerve cells cross from one side to the other medulla oblongata - basic life functions origin for 10 of 12 cranial nerves controls respiration, blood pressure, heart rate

Spinal Cord housed within vertebral column continuos with brain stem ascending and descending nerve tracts protected by CSF and meninges gray matter in internal section - not protected by myelin sheath myelinated white matter in outer area

Meninges dura mater arachnoid pia mater epidural subdural subarachnoid space contains CSF pia mater blood vessels and lymph

Bell’s Palsy Facial paralysis Treatment functional disorder of VII cranial nerve asthenia keratitis dysphasia Treatment anti-inflammatory drugs

Cerebrovascular Disease Arteriosclerosis cerebrovascular accident (CVA, apoplexy) ischemia transient ischemic attack hemiparesis hemiplegia aphasia ataxia

Seizure Disorders Epilepsies Convulsions dysrhythmias in the brain etiology: brain injury, congenital anomalies, metabolic disorders, brain tumors Convulsions

Parkinson’s Disease Progressive neurological disorder deterioration of portion of brain controlling movement bradykinesia, hypokinesia, tremors, shuffling gait. Treatment: l-dopa

Multiple Sclerosis Progressive degenerative disease of CNS Inflammation, hardening, and loss of myelin throughout spinal cord and brain Impeded transmission of electrical impulses tremors, muscle weakness, slowness of movements etiology: autoimmune, or slow virus

Alzheimer’s Disease Progressive neurological disorder plaques develop in cerebral cortex memory loss, cognitive decline, and personality changes leading cause of senile dementia research: some meds prevent breakdown of brain chemicals

Oncology Intracranial tumors Signs and Symptoms primary sites metastatic sites Signs and Symptoms headaches papilledema personality changes

Agnosia asthenia ataxia cerebral palsy closed head trauma coma concussion Guillian-Barre syndrome herpes zoster (shingles)

Huntington’s chorea hydrocephalus lethargy neural tube defect paraplegia paresis

transient ischemic attack (TIA) Paresthesia poliomyelitis quadriplegia Reye’s syndrome sciatica syncope vasovagal transient ischemic attack (TIA)

Cerebral angiography echoencephalography electroencephalography (CCG) myelography computed tomography (CT scan)

Surgical and Therapeutic Procedures Cryosurgery spinal puncture, spinal tap trephination vagotomy

Pharmacology Analgesics \anticonvulsants antidepressants hyponotics opiates psychtropic drugs sedatives tranquilizers

Abbreviations ALS ANS CNA CP CSF CT scan CVA CVD

Abbreviations EEG ICP LP MRI MS R/O TIA

End Chapter 15 Nervous System